Front Range eyes more Colorado River diversions

The Colorado River flows through Hot Sulphur Springs earlier this year.

The nascent Colorado Water Plan has begun to materialize in the form of draft implementation plans for each of the state's eight largest river basins.

And Front Range interests are once again looking toward the Colorado River to cushion water demand in the face of rising populations and interstate water obligations on the other side of the divide.

The Colorado General Assembly passed the Colorado Water for the 21st Century Act in 2005, which established roundtables for the state's largest river basins.

These roundtables were tasked with preparing water needs assessments for their respective areas, assessing water supply availability and identifying methods to address their water needs.

Gov. John Hickenlooper issued an executive order directing the Colorado Water Conservation Board to establish a statewide water plan in the face of increasing gaps between water supply and demand.

These findings were incorporated into the Statewide Water Supply Initiative in 2010. Each roundtable then developed a Basin Implementation Plan to address the needs identified in the Statewide Water Supply Initiative.

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Each roundtable released its draft plan last week, and the joint draft plan from the South Platte and Metro roundtables, which includes the Denver Metro Area, identifies new Colorado River water supplies as one of the "four legs of the stool" to address water needs in the South Platte River Basin.

The draft plan cites a growing population in the South Platte River Basin and obligations to send water to other states as major factors that justify additional trans-mountain diversion.

As of yet, the South Platte and Metro roundtables haven't established just how much extra water it would need to divert from the Colorado River.

"There's a lot of speculation out there from different folks, but I think the basin plan was very deliberate not to put a number to it because it really seemed to stall the conversation," said Sean Cronin, the chair for the South Platte Roundtable. "It really felt like it was more prudent that we ought to be having a discussion about additional supplies, and we ought to be having a discussion about what those additional supplies would look like."

The South Platte and Metro roundtables saw that the gap between water supplies and water demands on the West Slope left room for additional diversions, Cronin said. Additional diversions would also be limited to wet years, when more water is available.

"In the end, it really wasn't a matter of how much water," Cronin said. "It was simply a matter of do we want to pursue this idea for the greater good for Colorado."

But the Colorado River Basin Roundtable's draft plan doesn't view its resources as expendable.

"We think that a new project should be the last thing that's sought in that there still might not be enough resources or water to make that viable," said Jim Pokrandt, chair of the Colorado River Basin Roundtable. "We base that on the fact that the we are already big donors of water to the Front Range."

The Colorado River Compact of 1922 set limits on the amount of water that states can take from the Upper Colorado River Basin, and Pokrandt said overdevelopment on the river has pushed water use to its limits.

"We're close to the end if we haven't already hit the end," he said.

New players in diversion

Some thought the end of trans-mountain diversion could come with the 2013 Colorado River Cooperative Agreement, which saw Denver Water guarantee West Slope water providers and governments a cooperative process for any additional trans-mountain diversions in return for support for the Gross Expansion Project, which would see Denver Water divert an additional 18,000 acre-feet per year from the Colorado River.

But as Mark Koleber, chair of the Metro Roundtable, explained, Denver Water doesn't supply all of the Denver-Metro area and outlying parts of the South Platte River Basin.

"The metro area is much larger than that outside of the Denver water system," Kobeler said. "So what might be provided by the Moffat-Gross expansion wouldn't necessarily go to areas outside of the Denver Water service area unless they have a contract for it."

This means another entity could seek permitting for a trans-mountain diversion project from the Colorado River, which wouldn't fall under the Colorado River Cooperative Agreement.

But Pokrandt said any additional diversions to the South Platte, in theory, would have to come from other basins like the Yampa or the Gunnison.

"Some new big trans-mountain diversion would probably have to go somewhere else," Pokrandt said. "It would have to go somewhere else that's not hard hit."

Plan focuses on ag, environment

The draft basin implementation plan issued from the Colorado River Basin Roundtable has found that additional transmountain diversion would damage agriculture and degrade environmental conditions in the Colorado River basin.

"There's already so much water taken out of the headwaters that we don't think that there's any more water to give without severe economic and environmental degradation," Pokrandt said.

Under the Colorado River Compact, too much diversion in the Upper Colorado River Basin could lead to a "compact call," in which junior water rights holders in the upper basin must stop diverting to supply Lower Basin states with water.

"When you think of the bigger picture, the Colorado River system doesn't face (a compact call) yet, but if it did, junior water rights holders would be forced not to divert water, including many West Slope municipal users," Pokrandt said. "The Colorado Big Thompson Project, Denver Water, the Frying Pan Arkansas Project, all of these folks would be subject to curtailment if we overdevelop the river."

Each roundtable will submit its final plan to the Colorado Water Conservation Board in April 2015. The board will submit the final state water plan to the governor in December 2015.